MAb Passive Vaccination against Acinetobacter baumannii

项目概要/摘要 与其他耐药细菌相比，几乎没有抗生素在管道中处理XDR A。鲍曼不动杆菌。 迫切需要新的战略来预防和治疗这些感染。我们花了第一个补助期 将单克隆抗体提高至A.鲍曼不动杆菌囊膜，并且现在已经鉴定了4种抗囊膜单克隆抗体（其中2种用于 产生双特异性MAb，留给我们3个MAb分子），其共同结合80-90%的US临床 隔离并保护小鼠免受致命感染。这3个主要候选人都是非常有效的，达到100% 菌血症模型中≤ 50 µg单次给药的保护作用。它们在肺炎模型中也有保护作用， 感染，并与抗菌药物协同作用。此外，双特异性MAb具有与单克隆抗体相比增加的效力。 与其各个单克隆抗体结合，并保留与所有靶菌株的结合和体内功效。三号线索- 单克隆抗体治疗已经开始转化为完整的GMP和毒性，计划未来的I期临床试验。 我们的更新目标是提高临床开发和部署的可行性， 通过消除针对国际菌株的任何覆盖率差距，定义替代疗效标志物， 验证关键分析以支持临床试验和未来的临床部署。我们获得了一个新的全球 菌株收集，并建立了关键的伙伴关系，以进一步实现这些目标，包括多价单克隆抗体专家 临床微生物实验室操作和统计学。我们的目标是： 具体目标1：定义和优化国际标准的菌株覆盖率和替代有效性标志物 临床菌株A.鲍曼不动杆菌。我们从台湾、东南亚、中国、 欧洲和南美。我们将针对所有获得的菌株调查我们的3种单克隆抗体， 和巨噬细胞摄取，并将评估代表性菌株在我们的IV菌血症模型中的功效。我们 将根据需要增加新的MAb，以缩小国际菌株覆盖范围的差距。 具体目标2：单克隆抗体临床试验的生物测定，包括效价和人 替代疗效标志物。我们将验证LC-MS/MS的特定氨基酸序列， 可变区，以量化我们的单克隆抗体时，掺入人血，从背景抗体不同。我们 将采用我们成熟的HL-60测定来量化人血浆中MAb的调理素活性。最后我们 将使用多重Luminex测定来定量新鲜人白细胞的细胞因子调节。 具体目标3：优化作为“敏感性试验”的快速体外结合试验-等同于 支持单克隆抗体的临床试验和部署。我们将验证快速、高通量的流绑定 作为“敏感性试验等效物”，与小鼠中的保护相关的试验。 新的解决方案A.鲍曼不动杆菌感染是一个尚未满足的关键需求。我们已经开发出一种很有前途的单克隆抗体 该方案改善了小鼠血液和肺部感染期间的结果。我们将定义全球应变 覆盖范围，填补任何已确定的空白，并开发生物测定以支持单克隆抗体的临床试验。

PROJECT SUMMARY/ABSTRACT In contrast to other resistant bacteria, virtually no antibiotics are in the pipeline to deal with XDR A. baumannii. There is a critical need for new strategies to prevent and treat these infections. We spent the first grant period raising MAbs to A. baumannii capsule, and have now identified 4 anti-capsular MAbs (2 of which were used to generate a bi-specific MAb, leaving us with 3 MAb molecules) that collectively bind to 80-90% of US clinical isolates and protect mice from lethal infection. These 3 lead candidates are all highly potent, achieving 100% protection in bacteremia models at single doses of ≤ 50 µg. They are also protective in pneumonia models of infection, and synergize with antibacterials. Furthermore, the bi-specific MAb has increased potency compared to each of its individual MAbs, and retains binding for all target strains, and efficacy in vivo. This lead three- MAb therapeutic has begun translation into full GMP and toxicity, planning for a future Phase I clinical trial. Our goals for the renewal are to enhance feasibility of clinical development and deployment of the MAbs by closing any coverage gaps against international strains, defining surrogate efficacy markers, and validating key assays to support clinical trials and future clinical deployment. We have obtained a new global strain collection, and entered into key partnerships to further these aims, including experts at multi-valent MAb synthesis, clinical microbiology laboratory operations, and statistics. Our Aims are to: Specific Aim 1: Define and optimize strain coverage and surrogate efficacy markers for international clinical strains of A. baumannii. We have collected 50 strains each from Taiwan, Southeast Asia, China, Europe, and South America. We will survey our 3 MAbs against all acquired strains, assessing flow binding and macrophage uptake, and will assess efficacy in our IV bacteremia model for representative strains. We will raise news MAbs as needed to close international strain coverage gaps. Specific Aim 2: Validate bioassays to enable clinical trials of the MAbs, including potency and human surrogate efficacy markers. We will validate LC-MS/MS for the specific amino acid sequences of our variable regions to quantify our MAbs when spiked into human blood, distinct from background antibodies. We will adapt our well-established HL-60 assays to quantify opsonic activity of MAb in human plasma. Finally, we will use multiplex Luminex assays to quantify cytokine modulation of fresh human leukocytes. Specific Aim 3: Optimize a rapid in vitro binding assay as a “susceptibility testing”-equivalent to support clinical trials and deployment of the MAbs. We will validate rapid, high throughput flow binding assays to correlate with protection in mice as a “susceptibility-test equivalent”. Novel solutions for A. baumannii infections are a critical unmet need. We have developed a promising MAb regimen that improves outcomes during blood and lung infection in mice. We will define global strain coverage, close any identified gaps, and develop bioassays to support clinical testing of the MAbs.